Energy storage circuit

Abstract

An energy storage (ES) circuit, including: a plurality of terminals configured to: connect to a pulse load having an input voltage and drawing a low current during a first interval and a high current during a second interval; and connect to a power supply having a source voltage and delivering a source current; an energy storage capacitor connected to the plurality of terminals; and a bidirectional direct current (DC) to DC converter configured to: recharge, during at least a portion of the first interval, the energy storage capacitor using a plurality of charge drawn from the source current; and reduce a drop in the input voltage during the second interval by delivering a difference between the source current and the high current to the pulse load using the plurality of charge stored in the energy storage capacitor.

What is claimed is: 
     
         1 . An energy storage (ES) circuit, comprising:
 a plurality of terminals configured to:
 connect to a pulse load having an input voltage and drawing a low current during a first interval and a high current during a second interval; and 
 connect to a power supply having a source voltage and delivering a source current; 
   an energy storage capacitor operatively connected to the plurality of terminals; and   a bidirectional direct current (DC) to DC converter configured to:
 recharge, during at least a portion of the first interval, the energy storage capacitor using a plurality of charge drawn from the source current; and 
 reduce a drop in the input voltage during the second interval by delivering a difference between the source current and the high current to the pulse load using the plurality of charge stored in the energy storage capacitor. 
   
     
     
         2 . The ES circuit of  claim 1 , wherein the drop is based on current limiting of the power supply. 
     
     
         3 . The ES circuit of  claim 1 , wherein the drop is based on the high current and a distribution impedance of a conductor operatively connecting the power supply to one of the plurality of terminals. 
     
     
         4 . The ES circuit of  claim 1 , wherein the bidirectional DC to DC converter comprises:
 a synchronous switching regulator; and   a plurality of separate unidirectional power converters integrated using the synchronous switching regulator.   
     
     
         5 . The ES circuit of  claim 1 , further comprising:
 a voltage regulation interface (VRI) circuit configured to control, based on the input voltage to the pulse load, a feedback voltage applied to the bidirectional DC to DC converter,   wherein the bidirectional DC to DC converter delivers the difference based on the feedback voltage.   
     
     
         6 . The ES circuit of  claim 5 , wherein the VRI circuit comprises:
 a bipolar junction transistor (BJT) comprising a base, a collector, and an emitter;   a zener diode connected to the base of the BJT and the energy storage capacitor; and   a resistor connected to the collector of the BJT and a terminal of the plurality of terminals.   
     
     
         7 . The ES circuit of  claim 5 , wherein the bidirectional DC to DC converter comprises:
 a current bidirectional buck-boost power stage to charge the energy storage capacitor to a voltage greater than the source voltage during the first interval.   
     
     
         8 . The ES circuit of  claim 5 , wherein the power supply reduces the source current during the first interval after the energy storage capacitor is fully charged. 
     
     
         9 . The ES circuit of  claim 5 , wherein the energy storage capacitor comprises a first capacitor in parallel with a second capacitor. 
     
     
         10 . The ES of  claim 1 , wherein the power supply has a continuous output current rating, and wherein having the source current present during the second interval and during the portion of the first interval allows a greater percentage of the continuous output current rating to be applied to the pulse load. 
     
     
         11 . A method for operating an energy storage (ES) circuit comprising an energy storage capacitor and a plurality of terminals, the method comprising:
 drawing, by the ES circuit, a plurality of charge from a source current delivered by a power supply having a source voltage,   wherein the plurality of terminals connect to the power supply and to a pulse load having an input voltage and drawing a low current during a first interval and a high current during a second interval;   recharging, during at least a portion of the first interval and by a bidirectional direct current (DC) to DC converter of the ES circuit, the energy storage capacitor using the plurality of charge; and   reducing, by the ES circuit, a drop in the input voltage during the second interval by delivering a difference between the source current and the high current to the pulse load using the plurality of charge stored in the energy storage capacitor.   
     
     
         12 . The method of  claim 11 , wherein the drop is based on current limiting of the power supply. 
     
     
         13 . The method of  claim 11 , wherein the drop is based on the high current and a distribution impedance of a conductor operatively connecting the power supply to one of the plurality of terminals. 
     
     
         14 . The method of  claim 11 , wherein the power supply reduces the source current during the first interval after the energy storage capacitor is fully charged. 
     
     
         15 . The method of  claim 11 , wherein the energy storage capacitor comprises a first capacitor in parallel with a second capacitor. 
     
     
         16 . The method of  claim 15 , further comprising:
 controlling, by a voltage regulation interface (VRI) circuit of the ES circuit, a feedback voltage applied to the bidirectional DC to DC converter based on the input voltage to the pulse load,   wherein the bidirectional DC to DC converter delivers the difference based on the feedback voltage.   
     
     
         17 . The method of  claim 16 , wherein the VRI circuit comprises:
 a bipolar junction transistor (BJT) comprising a base, a collector, and an emitter;   a zener diode connected to the base of the BJT and the energy storage capacitor; and   a resistor connected to the collector of the BJT and a terminal of the plurality of terminals.   
     
     
         18 . The method of  claim 16 , wherein recharging the energy storage capacitor comprises:
 boosting, by the bidirectional DC to DC converter, a voltage at a terminal of the ES circuit to charge the energy storage capacitor to a voltage greater than the source voltage.   
     
     
         19 . The method of  claim 11 , wherein the DC to DC converter comprises:
 a synchronous switching regulator; and   a plurality of separate unidirectional power converters integrated using the synchronous switching regulator.   
     
     
         20 . The method of  claim 11 , wherein the power supply has a continuous output current rating, and wherein having the source current present during the second interval and during the portion of the first interval allows a greater percentage of the continuous output current rating to be applied to the pulse load.